A redundant configuration method of an operation server in which a spare server is set in advance for an operation server for executing a job and the spare server is allowed to automatically take over the job executed by the operation server in a case in which failure occurs in the operation server is conventionally known. Also, a method of realizing the operation server and the spare server on a virtual machine is known. The virtual machine is a virtual electronic computer in which computer hardware of a virtual computer system is logically divided and each of them operates independently.
When the operation server and the spare server are realized on the virtual machine, an operating system (OS) of the virtual machine of an operation system for executing the job is copied in advance to memory means of a spare virtual machine. The spare virtual machine has the same function as the virtual machine of the operation system by being operated by the OS copied to the memory means. Then, the spare virtual machine takes over the job performed by the virtual machine of the operation system when the failure occurs in the OS of the virtual machine of the operation system.
Patent Document: Japanese Laid-open Patent Publication No. 2007-219757
In the conventional art, the virtual machine of the operation system and the spare virtual machine operate on the same hardware. Therefore, when the occurred failure is attributed to the hardware, it is required to continue the job by allowing different hardware to take over the job as the spare server.
However, switching from the virtual machine of the operation server or the operation system to the spare server is accompanied with a copy process of the OS from the virtual machine of the operation server or the operation system to the spare server. Then, after the copy process of the OS is terminated, the spare server operates. Since the copy process of the OS takes a lot of time, the job stops during the same. Therefore, in a system in which continuity of the job is important, the continuity of the job is not sufficiently assured.